Figure 3

XRD patterns Raman spectra of SnO _x nanopore films. (a) XRD patterns of the as-prepared sample and SnO _x formed at varying oxidation temperatures of 350°C, 450°C, and 550°C. The symbol (O) indicates the substrate (Al₂O₃) reflections. The phases detected in the film are indicated as follows: I = Sn; V = SnO; asterisk = Sn₂O₃; T = SnO₂. (b) Evolution of the Raman spectra of SnO _x nanopore films prepared at 350°C, 450°C, and 550°C.